The present invention relates to a series of novel phosphorus-containing compounds and their use as a flame retardant.
Besides conventional building materials and textiles, a polymeric material is required to have flame retardance when used in the fabrication of an electronic device, e.g. a printed circuit board, encapsulation resin of an integrated circuit (IC), and electronic connectors, etc. In order to increase the flame retardance of an polymeric material, an addition of a flame retardant is used to achieve this objective regardless of whether the polymer is a thermoset resin or a thermoplastic resin. Organic phosphorus compounds have been widely used as a halogen-free flame retardant to improve or solve the problems such as the formation of toxic fume, corrosion, contamination of dioxin, etc. associated with the use of a halogen-containing flame retardant. Among which, phosphates including aliphatic or aromatic phosphates were widely used in the current products, e.g. triphenylphosphate, tricresylphosphate, and triethylphosphate, etc. These phosphates, after being added into a resin, may cause defects such as insufficient thermal stability and undesired high migration, etc. Therefore, some phosphate oligomers, such as dipolymer of resorcinol diphenyldiphosphate and its oligomer (e.g. Japan Patent 223158, U.S. Pat. No. 5,204,394, and U.S. Pat. No. 5,618,867, etc.), phosphate oligomers having a substituent (e.g. U.S. Pat. No. 5,506,313, EP-A-0456605, and EP-A-0509506, etc.), etc. were developed as a halogen-free flame retardant.
In addition to the requirements of good flame retardance, a polymeric material used in the fabrication of an electronic device also requires excellent electric characteristics, thermal stability, and dimensional stability. The addition of a flame retardant, more or less, will have a certain degree of influence on the properties of the polymeric material. Consequently, it is important for the flame retardant to meet these requirements for this use.
One objective of the present invention is to provide a series of phosphorous-containing compounds with a novel chemical structure.
Another objective of the present invention is to provide a series of novel phosphorous-containing compounds as a flame retardant.
Another objective of the present invention is to provide a flame retardant resinous composition comprising, as a flame retardant, a phosphorous-containing compound of the present invention.
Another objective of the present invention is to provide a cured flame retardant resin which is prepared by cross-linking a flame retardant resinous composition of the present invention.
Still another objective of the present invention is to provide a flame retardant polymer, which is prepared by performing a polymerization reaction of a phosphorous-containing compound of the present invention as a monomer, or a co-polymerization reaction of a phosphorous-containing compound of the present invention as a monomer and another monomer.
In order to achieve the above-mentioned objectives of the present invention, a phosphorous-containing compound synthesized according to the present invention has the following chemical formula (I): 
wherein R1-R8 independently are H or C1-C4 alkyl; Y is xe2x80x94OH or 
wherein R1-R4 are defined as above; Q is H, xe2x80x94NO2, xe2x80x94NH2, xe2x80x94OH, xe2x80x94CH3, xe2x80x94CHO, xe2x80x94COOH, 
R9 and R10 independently are H or C1-C4 alkyl; and A is xe2x80x94Oxe2x80x94, 
xe2x80x94CH2xe2x80x94, or xe2x80x94C(CH3)2xe2x80x94. 
Preferably, X in the formula (I) is Q.
Preferably, X in the formula (I) is 
Preferably, R1-R8 in the formula (I) are H, Y is 
Preferably, Q in the formula (I) is xe2x80x94NH2.
Preferably, Q in the formula (I) is xe2x80x94OH.
Preferably, Q in the formula (I) is 
Preferably, A in the formula (I) is xe2x80x94Oxe2x80x94.
Preferably, A in the formula (I) is 
Preferably, A in the formula (I) is 
The present invention also provides a flame retardant resinous composition comprising a phosphorous-containing compound having the formula (I).
The present invention also provides a cured flame retardant resin which is prepared by cross-linking the flame retardant resinous composition of the present invention.
The present invention further provides a flame retardant polymer, which is prepared by performing a polymerization reaction of a phosphorous-containing compound having the formula (I) as a monomer, or a co-polymerization of a phosphorous-containing compound having the formula (I) as a monomer and another monomer.
The phosphorous-containing compound (I) of the present invention has the advantages, such as easy to be synthesized, providing a resin of high phosphorous content and high thermal resistance, etc., and thus is suitable to be used as an additive or made into various types of organic polymeric material with flame retardance.